Modification of stereoregular polyolefin with hydrophilic copolymers



United States Patent 3,484,838 MODIFICATION OF STEREOREGULAR POLY- OLEFIN WITH HYDROPHILIC COPOLYMERS Jack J. Press, 12-18 E. Laurelton Parkway, Teaneck, NJ. 07666 No Drawing. Continuation of application Ser. No.

400,612, Sept. 30, 1964, which is a continuation-inpartof application Ser. No. 113,972, Apr. 4, 1961. This application Feb. 7, 1968,,Ser. No. 703,784

Int. Cl. C08f 33/08 U.S. Cl. 260-895 Claims ABSTRACT OF THE DISCLOSURE A composition of stereoregular polypropylene and 2- of an organic-dye receptive modifier consisting of a copolymer of N-vinyl and the like pyrrolidone and certain ethylenically unsaturated monomers. a I

, The invention described herein may be manufactured and used by or for theGovernrnent of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This is a streamlined continuation of my copending application Ser. No. 400,612, filed Sept. 30, 1964, which Ser. No. 400,612 is a continuation-in-part application of my Ser. No. 113,972, filed Apr. 4, 1961, each now abandoned.

, The invention relates to stereoregular polyolefins. More particularly, this invention relates to polymeric compositions having improved afiinity for dyes, said compositions containing a major amount of stereoregular polyolefins.

It is known that polyethylene is vastly unsuitable for the production of textile fibers due to the relatively poor properties imparted to the product. For one thing, a staple polyethylene fiber will not hold a crimp and this is necessary for textile processing. For another, it is useless to make a textured or stretched yarn from a continuous polyethylene filament because the characteristics imparted to the yarn are not maintained during weaving, dyeing, or ordinary use. Further, the material from which a fabric is made must be thermally stable before it may be subjected to ordinary use. It must not have a relatively low melting point, and the final fabric must not have a high degree of heat sensitivity, nor relatively soft mechanical properties at elevated temperatures. However, the thermal properties of a polyethylene fabric are such that it is impossible to subject it to ordinary ironing Without physically damaging the fabric and it has been found to shrink in the conventional dryer. As is apparent from the foregoing, polyethylene cannot be utilized in the manufacture of everyday fabrics for ordinary use.

In recent times, it has been found that certain linear crystalline hydrocarbon polymers containing stereoregular macromolecules and having melting points between 150 and 300 C. can be used for the production of textile fibers without the inherent difiiculties encountered with the use of polyethylene polymers for this purpose. Aside from melting point differences, polypropylene with a tertiary carbon and a methyl side chain, crystallizes differently and has a much higher resilience and elasticity. These properties are essential in generally useful textile fiber. Further, polymers of olefinic hydrocarbons containing stereoregular macromolecules, such as polypropylene, polymethylpentene, and polymethylbutene, ofier considerable advantages in the production of fibers, particularly because of their good mechanical properties and light weight. However, such polymers have not been satisfactory because of their poor affinity for dyes, this poor afiinity being due to the particular chemical nature of such polyolefinic hydrocarbons.

Many processes have been proposed in order to improve the affinity of such polyolefinic hydrocarbons for dyes, such as the addition of soluble solid substances to the molten polyolefin before spinning. The addition of basic substances facilitates dyeing with acid dyes, whereas the addition of acid substances favors dyeing with basic dyes. However, such processes have not been completely satisfactory because soluble modifiers interfere with crystallization, impair strength and thermal stability, and are not sufiiciently available in the amorphous regions where dyeing takes place.

It has also been proposed to increase the affinity of dyes for polyolefin fibers by grafting monomers onto the fibers after subjecting the fibers to a preliminary peroxidation or to high energy radiation. When such processes are applied to the polyolefin after it is in filamentary form the surface properties of the grafted fibers are considerably modified and the dye receptivity is improved. However, when such processes are applied to highly crystalline filaments, any grafting onto the preformed fibers takes place only at the surface. Therefore, subsequent dyeing is limited to the surface portion of the fiber and the dye does not penetrate inside the fiber.

In my copending application titled Modification of Stereoregular Polyolefins, Ser. No. 400,611 filing date Sept. 30, 1964, now US. Patent 3,366,710, I teach that the affinity of polyolefins for dyes may be enhanced through the use of selected hydrophilic, non-soluble polymers.

Now, I have discovered that the alfinity of polyolefins may be further improved, over and above the improvement achieved with the above polymeric materials, if the modifier incorporated in the polyolefin is one of a specified class of copolymers. Also, .I have found that this class of modifiers exhibits less intramolecular c'ohesion thus increasing the ease with which the modifier can be uncoiled or unfolded and formed into a continuous network in the amorphous regions of the polyolefins where dyeability is enhanced.

An added advantage, lies in the fact that good dyeability is achieved with lower molecular weight modifiers which are more desirable to use. Usually, with homopolymeric modifiers, you must utilize high molecular weights to achieve improvement in dyeability. However, lower molecular weight modifiers disperse more readily in the polyolefin, are easier to prepare, and one can work with more concentrated solutions to achieve the same result. I a

It is therefore an object of this invention to provide a polymeric composition having improved aflinity for dyes devoid of all the difficulties of the prior art.

This invention relates to stereoregular polyolefins having increased aflinity for dyes and other polar substances comprising a matrix of a stereoregular polyolefin taken from the group consisting of polypropylene, polymethylpentene, and polymethylbutene, said matrix of polyolefin having dispersed therein between about 2 and 20% of a modifying co-polymer which is hydrophilic, nonsoluble in the polyolefin, and fusible at a temperature between 150 C. and 350 C., said modifying copolymer being selected from the group consisting of:

(a) 30 to 70% N-vinyl pyrrolidone/30 to 70% vinyl acetate (b) 60% N-vinyl pyrrolidone/40% vinyl methyl ether (c) N-vinyl pyrrolidone/20% styrene (d) 70% N-viny1pyrrolidone/30% ethyl acrylate (e) 70% N-isopropyl pyrrolidone/30% ethylene oxide (f) 60% N-acryl pyrrolidone/40% ethyl acrylamide (g) th50% N-vinyl methylpyrr-olidone/5 0% vinyl methyl e er 3 (h) 60% N-vinyl oxazolidone/40% acrylonitrile (i) 70% N-vinyl oxazolidinone/ 30% hydropropyl methacrylamide (j) 50% N-vinyl methyloxazolidinone/50% vinyl acetate from 0.5 to 2% of the dye on the weight of the sample. The following dyes were utilized in separate baths viz. AMR-Clour Index, Acid Red 182;

ARColour index, Acid Red 127;

DO-Colour Index, Disperse Orange 3; and

(k) 60% N-vinyl morpholinone/40'% methyl acrylate 5 DLVLatyl violet 2R, disperse dye.

and The d e baths were each heated over an hour to a (I) 90% N'vmyl pyrrohdone/ ethylene temperatiire of about 95 C. and the temperature was all said percentage being percent by weight of the overall maintain d for 2 hours, The dye samples were then composition. 10 rinsed, given a 10 minute 95 C. launder in the dye pot A preferred class of my modifiers consists of polymers at a 20 to 1 bath to sample ratio with a 5 gram per gallon derived from oxygen containing N-alkenyl heterocyclic Tide detergent solution. The samples were then rinsed, monomers, particularly alkenyl substituted lactams, dried, and judged for depth and uniformity of shades. The oxazolidone, oxazolidinone and morpholinone monomers. results of such test are set forth in the table below: This class of polymers is highly desirable because it has DISCS little or no basicity and has very high levels of affinity for a wide range of dyes. My preferred primary modifiers b c d are neutral or only very slightly basic and yet in poly- Percent addition 5 5 10 15. olefins, surprisingly, have higher dyeability with anionic y gi 5 g gig: (acid) dyes than the much more basic polymeric modi- Dispersibilityirrpoly: j fiers. In these monomers and polymers, the alkenyl subgf fii with Poor/fair" Fan/good stituted nitrogen is part of an internal amide group and (a) DLV,DO Light Med Dark Dark. is essentially neutral. Additional ring and substituted (b) AMAR'ARm' Undyed" Med Dark oxygen containing groups are more acidic than the sub- Vaviuv tat ;V0 y Y stituted amide nitrogen and further reduce basicity. As indicated the dispersion f the homopolymer b The Stereoregular Polyolefins which may be used with itself was poor to fair. The copolymer dispersed readily. in the concept of this invention include isotactic and Both the homopolymer and the eopolymelgave a li ht syndiotactic polyolefins. These materials are usually made incl-ease i opacity wi dispersed dyes, the homoPolyby utilizing stereo-specific catalysts which give polymers gave a light Shade and the eopolymer a di which are substantially linear and which develop a high Shade which could be increased t0 3 dark Shade by i degree of crystallinitycrease in concentration.

The following examples will illustrate the utility of the present composition: EXAMPLE 2 EMMPLE 1 r In this example, tests similar to those of Example 1 A 30 were preformed except that, in this case the modifier condiscs. of m the foilowmg manner taining polyolefin was extruded into fiber, drawn and then l as modlfier elther Poly dyed using conventional equipment and processes. OXaFOhdmOIe (D Chemlcal 5 alpne The formulation was melt mixed in a continuous screw or in a balanced weight fractlon copolymer with v1nyl extender forced through a 60 mil die at C- and acetate. (Devlex OW Che.m1.ca1 5 40 collected at ambient temperature on a reel as a 30 denier Yarious percent addrtrons, as indicated 1n the table filament. ge g ffg g gg g 33 x5 32: The filament was then heat stretched 30mm give of a powdered i conglmercial a strong, oriented 1O denier fiber. The fiber skeins were inhibited isotactic polypropylene (molecular w ei ht the-n scoured Wlth detergent at 140 and-dyed at the b t 350 000 m M t b t C It g boil for one hour at a 20/1 bath to fiber ratio. a Hg P m a Cu me m 6X The filament, as spun was judged subjectively for unlof 3, and 1sotact1c1ty of 95%). f f f th 1 I fi d The mixtures were then air dried (to remove some Omny-0 118p BIS-Ion 0 mo 1 er m 6 yoe n an o the dyemgs were udged for level of dyeability. The resolvent) and then heated in a drying oven at 80 C. until Sults of Such tests are listed below, all of the solvent had been removed.

Each of the dried mixtures was prepared in the form TABLE of a disc in the following manner. The powder of each nt add 5 p b x polyolefin Goodv sample was spread uniformly in a circular shouldered Pmentvoom 25 ifi g iyggg Medium Pyrex glass dish with an inside diameter of 4 inches. Percentva A ZA g The dishes were then covered by an inner nesting circular shouldered Pyrex glass dish with a bottom outer separa- EXAMPLE 3 tion rib projecting downwardly about 0.05 inch. The In accordance with the general procedure of Example assembly weighted with a preheated 5 pound Weight was 1, I prepared discs using as modifiers vinyl pyrrolidone then placed in an oven at 250 C. for 6 for 15 minutes. (K-30) alone and in copolymer relationship with vinyl Then the weight was removed and the assembly was acetate. The copolymers contained 70%, 50%, and 30% placed in a refrigerator at about 4 C. to cool. The asvinyl pyrrolidone (PVP/VA I735, I-535, and I-335, sembly dishes were then separated to give a fuzed disc. General Aniline & Film Corp.) respectively. The discs A portion of each of the fusion discs after water rinswere dyed, as heretofore described, and tested subjectively ing were individually placed in a separate dye pot tofor uniformity of dispersion and shade of coloration. gether with 20 times its weight of distilled water and The results of such tests are listed below:

DISCS a b c d Percent add 5 5 5 5. IercentVP 5 3.5 2.5 1.5. PercentVa 1.5 2.5 2.5. Dispersibility in Poor/fair Good Good/ Good/ polyolefin. excellent. excellent. Dyeability with- (a DLv, D0 Light Medium Medium Medium. (1)) AMR, AR Tint Medium Light Tint.

VP-Vinyl Pyrrolidone; VaViuyl acetate.

5 EXAMPLE 4 ,In accordance with the procedure of Example 2, the modifier containing polyolefin was extended into fiber, drawn, and then dyed using conventional equipment a d processes. In this case, the modifier utilized represented a 50/50 copolymer ofvinyl pyrrolidone and vinyl acetate and the concentration of this modifier in the polyolefin was varied. The final products were tested subjectively for uniformity of dispersion and depth of shake, and the results. were tabulated below:

Percent VP Dispersibility in Dyeability with-- LV, D0. Lightlmed. Medium. Dark Dark.

(b) AMR, AR Very light.- Light Medium VP-Vinyl Pyrrolidone: Va-Vinyl acetate.

As indicated above, the depth .of coloration of the polyolefin increased with increasing concentrations of the modifier.

is achieved in the affinity of the polyolefin for dyes, when one of the specific copolymers listed is utilized as modifier.

P t Plsrtsent ercen e ero- D eab' it ratio Percent cyclic Dispersibility in y 11 y M d fi r (ii any) add monomer polyolefin (a) DLV DO (b) AMR, AR

(1) VP/vinyl methyl ether 60/40 4 Light (1A) Vinyl pyrrolidone (VP) 5 2.5 Undyed.

( VP/styre e 80/20 3 2, 4 Light (2A) Vinyl pyrrolidone (V P)-. 2- 5 5 Undyed 3 VP/ethyl acryl e 7 /30 3. 5 Light.

(3A) Vinylpyrrolidone (VP).. 3- 5 3.5 Light Tint.

(4) IP/ethylene oxide. 70/30 5 3. 5 Good/exeell Medium Medium (4A) Isoprenyl pyrrolidone (IP 3. 5 3. 5 Light Ti t,

(5) AP/ethyl acrylamide 60/40 6 Da' k Darin (5A) Aerylylpyrrolidone (AP) 6 6 Medium Light.

(6) VMP/viuyl methyl ether 50/60 10 5 Dark k,

( Vinyl methyl py olidone (VMP) a 5 Light/me Light (7) VO/acrylonitrile 60/40 5 3 ediurn Do.

(7A) Vinyl oxazelidone (V O) H 3 3 Light Tint.

g VO%/hydroxypropylmethacryla- 7 5 3.5 Good/excell Medium Medium.

(8A) Vinyl oxazolidinone (V 00) 3, 5 3, Tint.

(9) VMOO/methyl methacrylate 60/40 6 3. Light A) Vinyl morpholinone (VMOO) 3 0 Tint (10) VIP/ethylene 90/10 a 2 Light (10A) Vinyl pyrrolid ne (VP) 0 3. Undyed.

EXAMPLE 5 In accordance with Example 1, I prepared discs using as modifiers /50 copolymers of vinyl pyrrolidone and vinyl acetate having the following molecular Weights viz. 10,000; 40,000; and 160,000. The discs were dyed and tested, as heretofore described, for uniformity of disper- Note that with increasing molecular weight of the modifier, the affinity of the polyolefin for dyes is increased.

EXAMPLE 6 In accordance with the procedure set forth in EX- ample 1, I prepared discs of polyolefin separately using Many alternate methods of combining my modifiers with polyolefins are readily available. They may be com bined during formation of the polymeric modifier or during actual polymerization of the polyolefin, with or without melting. They may be added to freshly polymerized polyolefin, which is still in solution. in a suitable solvent, in the powdered form, or as a solution in a com patible solvent, or merely as a dispersion. They may be added to the polyolefin during precipitation, washing, neutralizing or compounding of the freshly prepared polyolefin prior to drying. This may be accomplished by adding the modifier as a powder or as a solution which is a non-solvent for the polyolefin. a

The modifiers may also be melt mixed during processing or blending of the polymer prior to use in extrusion of fiber, film, coating or plastic. It may also be added as a liquid or powder to finely ground or micronized polyolefin polymers and then melt dispersed in situ during hot dip or spray coating or during. spreading and heat coating operation. They may be incorporated in polyolefin solutions or emulsion and then applied to surfaces with or without heating.

The level of addition of the modifiers heretofore listed should be between 2 and 20% of the weight of the overall composition. If less than 2% is utilized, significant improvement will not be achieved in dyeability. If an amount greater than 20% is added to the polyolefin, many of the physical properties of the final product, such as fiber or film, are adversely affected. These include loss of strength and a lower resistance to repeated flexing.

The copolymer should comprise at least 25% by Weight of an oxygen containing N-heterocycle monomeric unit in combination with not more than 75 of an ethylenically unsaturated monomeric unit having no basic groups. If the latter unit is present in an amount over 75 you obtain very low levels of dyeability. It is therefore necessary to use very excessive amounts of modifier to achieve desired results.

If the ethylenically unsaturated unit is present between 50 and 75% by weight, higher levels of addition are required. The melting point of the overall composition may be reduced to such an extent that the modifier, particularly at higher levels of addition, may give some problems in processing.

However, if the latter monomeric units are present below 50% by weight of the overall composition, lower levels of addition can be used to improve dyeability without processing problems resulting from an excessive reduction in melting point. This represents the optimum from a commercial point of view.

Prior efforts to develop polymeric modifiers for high melting polyolefins have stressed development and use of specific polymers with relatively high solubility in the polyolefin. These modifiers included polyimines and polyvinylpyridines.

Polyimines have high molecular mobility which apparently gives them some ease of solution in polyolefins. However, there is also a high tendency to sweat out and separate when the combination is made into fiber or film. On the other hand, soluble polyvinylpyridines confer little or no dyeability on the polyolefin when dissolved therein. This appears to be the case until the preformed modified polyolefin is post treated with epoxy compounds, concentrated acids, alkylating agents, nitrous oxide gas, and alkylene oxides. However, such post treatments are difficult, costly and generally impractical.

Under present concept, I prefer hydrophilic polymeric modifiers which may be soluble in either water or an oxygenated solvent but which are not soluble in the polyolefin. I do prefer modifiers which are fusible and can be dispersed in the polyolefin.

Prior experience with comparatively less hydrophobic fiber forming polymers, such as polyacrcylonitrile polymers and polyamides, have shown that the use of hydrophilic, water soluble or dispersible modifiers is impractical, mainly, because excessive amount of the modifier are leached out in scouring and dyeing processes. Surprisingly, I have found that my hydrophilic polymeric modifiers, when melt dispersed in the more hydrophobic polyolefin, have good dispersion stability and are not susceptible to leachage.

I have found that at comparatively low levels of addition, my modifiers confer good dyeability on the polyolefin without the necessity for costly and sometimes impractical post treatments.

My hydrophilic modifiers must be fusible with the polyolefin. This is necessary for the formation of a continuous network of modifier throughout the polyolefin in order to permit dye penetration and efiicient coordination of the dye and modifier throughout the film or fiber.

The use of a non-fusible cross-linked modifier, which results in poor dispersion, is ineffectual. The required modifier network in such a case cannot be formed and the discrete, separate particles are surrounded by unmodified areas within the polyolefin matrix. As a result, dyeing is limited to the fiber surface and the dye cannot penetrate into the interior of the fiber where it is most desired.

It is generally recognized that dyeing takes place almost entirely in the more open and readily accessible amorphous areas. When a soluble modifier is utilized, it is usually spread throughout the amorphous and crystalline areas of the polyolefin. As a result, the modifier in the crystalline areas is not available for improvement in dyeability. It also interferes with crystallization and adversely affects strength and thermal stability. However, my non-soluble, hydrophilic, polymeric modifiers are not sufficiently compatible to be a part of the more uniform and denser crystalline areas. It appears to concentrate in the more amorphous areas where it is necessary for dyeability. It has also been found that an increase in molecular weight of my modifiers, further reduces compatibility with stereo-regular polyolefins and promotes concentration of the modifier in the more amorphous regions where it may improve the dyeability of the polyolefinic matrix.

Obviously, many modifications and variations of the present invention are possible in the light of the above teaching. For instance, the modifiers of this invention may be used to increase opacity and the afiinity of the polyolefin for finishes. They may also be used to improve the printable of the polyolefin, increase the adhesion of the polyolefin to other materials, or to reduce the overall static propensity of the final product. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

I claim:

1. A composition having increased affinity for dyes which composition consists essentially of:

(I) A matrix of stereoregular polyolefin taken from the group consisting of polypropylene polymethylpentene, and polymethylbutene;

(II) dispersed throughout said matrix as a continuous network a hydrophilic modifier, non-soluble in said polyolefin, and fusible in a melt of said polyolefin, said modifier is a copolymer selected from the class consisting of, where said percentages are by weight of monomer content:

(a) 30% to 70% N-vinyl pyrrolidone/30% to 70% vinyl acetate,

(b) 60% N-vinyl pyrrolidone/40% vinyl methyl ether,

(c) N-vinyl pyrrolidone/20% styrene,

(d) 70% N-vinyl pyrrolidone/30% ethyl acrylate,

(e) 70% N-isopropenyl pyrrolidone/30% ethylene oxide,

(f) 60% N-acrylic pyrrolidone/40% ethyl acrylamide,

(g) 50% N-vinyl methylpyrrolidone/50% vinyl methyl ether, and

(h) N-vinyl pyrrolidone/ 10% ethylene, said modifier being present in an amount between 2 and 20 percent by weight of polypropylene plus modifier.

2. The composition of claim 1 wherein said copolymer is 30% to 70% N-vinyl pyrrolidone/30% to 70% vinyl acetate.

3. The composition of claim 1 wherein said copolymer is about 50% N-vinyl pyrrolidone/50% vinyl acetate.

4. The composition of claim 1 wherein said copolymer is about 70% N-vinyl pyrrolidone/30% ethyl acrylate.

5. The composition of claim 1 wherein said copolymer is about 60% N-acrylic pyrrolidone/40% ethyl acrylamide.

References Cited UNITED STATES PATENTS 3,256,364 6/1966 Bryant et al. 260-895 MURRAY TILLMAN, Primary Examiner M. J. TULLY, Assistant Examiner US Cl. X.R. 

